WO2015076680A1

WO2015076680A1 - Method and device for providing pipe joint in concrete wall

Info

Publication number: WO2015076680A1
Application number: PCT/NO2014/050219
Authority: WO
Inventors: Terje REIERSEN
Original assignee: Basal As
Priority date: 2013-11-21
Filing date: 2014-11-21
Publication date: 2015-05-28

Abstract

The publication relates to a method and a side core for fabricating a joint for a pipe extending through a concrete wall or concrete structure, such as for example a lower section (10) of a branching chamber, where prior to the concreting a side core (22) is established, the side core (22) being given an external shape adapted to the form to be established at least one joint in an aperture extending through a concrete wall or structure, and where the side core (22) for said joint being positioned at the required place between an outer formwork and an inner formwork for subsequent concreting, whereupon the side core (22) is removed upon completed concreting. The side core (22) for the joint comprises: - a first shape providing element (16) with a cross section that is configured such that the lower part of the cross section has a shape substantially adapted to a lower part of a downstream adjoining channel or duct (12',12''), so that an internally, at least a lower hydro dynamical surface is provided between an internal surface of a spigot end of an adjoining pipe and a consecutive downstream surface; - a second shape forming element (23) with an outer cross section which mainly is configured to in such way that the outer cross section is slightly larger than the outer diameter of a spigot end of a pipe (11,13) to be jointed in the joint in the concrete wall or structure, and - a mainly cylindrically shaped, form stable body (24) configured to form an aperture through the concrete wall or structure and preferably having an outer shape that is configured in such way that one or more contact areas are established for fixing of a sealing ring within the aperture for establishing a sealing fixation and/or joint between the surrounding concrete wall and the spigot end of the pipe (11,13) to be jointed, where at least said first and second shape providing body (16,23) are removed subsequent to completed concreting.

Description

METHOD AND DEVICE FOR PROVIDING PIPE JOINT IN CONCRETE WALL

The Technical Field of the invention

The present invention relates to a method and a side core for concreting of a connection point for a pipe or duct extending through a concrete wall or structure, such as for example a lower section of a distribution manhole, where in the concreting process a side core with a adapted outer shape for formation of at least one connecting joint in a hole extending through the concrete wall or structure, and where the side cores for the connecting joint through the wall of the manhole are placed in desired position between an outer and inner mould for consecutive concreting, whereupon the side core is removed subsequent to completed concreting.

Background for the invention

In a sewage, storm water or waste water systems, access chambers, access junction, inspections chambers or manholes chambers (hereinafter denoted manhole) are used, into which one or more pipelines connected. Such manhole may consist of a base unit, one or more chamber units stacked on top of the base unit and a taper or cone positioned on top of the upper chamber unit. Most commonly, such units in a manhole is made of concrete. The manhole is configured In order to facilitate for the inlet and outlet of pipelines into and out of a unit of a manhole, preformed holes for the pipelines may be provided in the wall of a base unit and/or chamber unit at appropriate positions.

There are numerous variables related to such type of manholes, such as for example the wall thickness of the base unit or chamber unit, the inner or outer diameter or surface curvature of the unit in question, the diameter of the pre-formed aperture through the wall, the outer and inner pipe diameter of the pipeline to be jointed, the shape and inner diameter of the terminating end of the spigot end to be jointed, possible inner diameter and socket shape to be formed inside the aperture, shape of the seal or gasket to be used, etc. Moreover, various configurations of the pre-formed or pre-benched bottom surfaces with various different configurations of channels for water flow through the manhole are a parameter adding up to a vast number of different solutions.

It should be appreciated that jointing points are established in that several different pipes or tubes are introduced into a manhole where the waste water from the different introduced pipe branches are interconnected inside the manhole for exiting out of the chamber through for example one single exit duct, For this purpose the manhole is internally configured with a branching system which is suitable adapted for the specific connecting point. In order to secure best possible

hydrodynamic flow of drained water through the manhole, the manhole is configured with curved ducts and curved duct cross sections from each of inlet pipes to a common exit pipe which may be provided with a larger cross sectional area for flow than the cross sectional area of flow for each of the supplying inlet pipes. Said duct system is provided with an open top and may for example have a U-shape.

The number of pipes that are to be introduced into such a manhole may vary. At the same time the diameter of the various pipes may vary for the one and same access chamber, dependent of the necessary capacity of the different supplying inlet pipes. The diameter and wall thickness of the manhole are also parameters that may differ. Therefore, this means that the manhole must be specifically adapted or purpose-built to meet the desired capacity and number.

It is known to produce an inverted shape for each socket. With several different materials and a variety of producers with different socket solutions and use of materials, and also different spigot ends of the various pipes, many different moulding forms are necessary in order to cater for all the variants, having an effect on the level of production costs.

US 3,36,876 shows a pre-cast base unit for a manhole including a channel system on the bottom interior of the base unit, where each channel is communicating with an end of a pipeline ended in a corresponding aperture in the base wall. For this purpose, the aperture is given a shape corresponding to an inner shape of a socket or bell mouth of the pipe in question. In order to provide the required shape of the aperture through the unit wall two insert members are assembled to one unit, said assembled unit being fixed to the moulding form as an extension of the channels in the interior base bottom. The insert members, when assembled, are given a shape outer shape which is meant to correspond to the internal shape of the aperture.

DE 10 2009 053 179 shows a moulding form consisting of a supporting structure in the form of a cylindrical body with a smooth vertical outer surface, positioned on a flat and horizontal plate. The diameter of the cylindrical body corresponds to the inner diameter of the base section. A shape providing body or mould for the channel system intended for forming the interior bottom is placed on top of the cylindrical body facing upwards. The shape providing body is provided with an upwards facing convex mould surface for formation of the low channels upon concreting. Each end of the part of the shape providing body for the inlet pipes and the outlet pipe is provided with an insert body intended to form the surface of the apertures, Said insert body is configured to be attached to the shape providing body or mould for the channel system.

DE 2857568 describes a corresponding insert body, configured to provide the surface of the apertures in the concrete wall of a base unit or a chamber unit.

Therefore, with the prior art solutions and with the prior art method of concreting, it is a need for a very large variety of configurations of moulds in order to establish a sealing joint within an aperture extending through the manhole wall, connecting the pipes to said flow channels in the lower part of the precast base. For the prior art concreting process a large number of different moulds for establishing the connection joints within the manhole wall are required. According to the prior art methods this is achieved by using an integrated body provided with a mould also for establishing a socket shaped cavity at the connection points within the manhole wall.

It should also be appreciated that during concreting the specific gravity of the concrete used is much higher than that of the mould for establishing the connection joints inside the wall of the manhole. Consequently said mould body will be exposed to a substantial compressive load from the surrounding concrete during the concreting, possibly causing deformation of said mould body.

In a joint of this type a problem area is linked to the joint, due to the possible ovality caused the pressure caused by the surrounding wet, green concrete, prior to curing of the concrete.

Moreover due to the light weight of the mould body compared to the concrete there exists a possibility of displacement of the mould body during the concreting stage, until the concrete is sufficiently cure to prevent such displacement.

There is therefor a need for a more simplified solution which makes it possible to more effectively and to a lower cost provide both a method and a device for production and use of the insert members configured to provide the required shape of apertures through the wall of the base or chamber units. Moreover, it is also a need for a method and a device for producing a more accurate shape, meeting the tolerance requirements for a water tight joint inside the concrete wall

It is also a need for a solution providing a fluid dynamic surface without edges or obstacles causing a hindrance of the flow.

Moreover, there is a need for a mould wherein the shape and/or contour of the dimension sensitive parts is maintained within required tolerances for the final joint to be established inside the manhole wall. In addition it is a need for securing correct position of the mould body during concreting. Summary of the invention

A main principle of the present invention is to establish a socket shaped connection surface inside the wall of a concrete base unit or chamber unit, such as a lower base section of a concrete manhole, in order to establish a preferably hydrodynamic and fluid tight joint for the pointed spigot end of a pipe to be jointed. The purpose of this socket shaped joint within the concrete structure is to secure that the joint, i.e. at least the lower part of the flow surface of the spigot end, the at least lower surface of the socket shaped aperture and the adjoining flow channel inside the manhole, along which joint, the fluid is flowing, is hydro dynamically smooth without upwards extending or projecting edges or other types of obstacle surfaces, caused by the joint.

Another main principle used according to the present invention is to use a socket shaper, arranged on a part of the aperture mould form, intended to face towards the interior of the manhole, the socket shaper having the negative or inverse shape of the socket to be arranged in conjunction with the spigot end of a tube to be jointed. The socket shaper is made of a material being able to withstand the loads and forces caused by pouring concrete into the form, without changing the shape of the socket former. Since the aperture mould body may be deformed by the

surrounding concrete pressure the socket shaper also contributes to the form stability of the aperture mould body. This may be necessary, since the aperture mould body does not necessarily do have the inherent rigidity or form stability itself, in particular not if the mould body do have an aperture extending through the body or if the aperture mould body is position at a level in the form where maximum concrete exposure on the aperture mould form may occur.

In order to perform the method according to the invention, a side core is used, intended to form the general contour surface of the aperture through the concrete wall. The dimension and contour of the side core is chosen in such way that at least a lower part of the liquid flow surface extending form the inner, surface from an adjoining pipe, the joint through the concrete and the flow channel inside the interior bottom surface of the manhole is flush without any substantial obstacles upon complete concreting operation. The side core comprises a first part provided with a shape corresponding to the contour of a portion of the aperture facing the interior of the manhole, hereinafter named as a stem shaped body. Moreover the side core comprises a portion having a larger cross sectional area than that of the stem shaped body, hereinafter named as a cap body. In addition a socket shaper, which preferably is formed by a form stable ring shaped body, mounted on the stem shaped body; and which subsequent to concreting and removal of the stem and cap shaped body, and possibly also the socket shaper, forms a recess in the concrete structure for receipt of a seal, if the socket shaper is removed, to enable the pointed spigot end of a pipe to be jointed with the concrete structure in a fluid tight manner.

By form stable means a body which in itself is so rigid that it does not deform when exposed to the intended forces and/or, which together with the body on which it is attached, is so rigid or incompressible that neither the outer shape, contour nor the inner shape is affected by loads and forces appearing during the concreting operations. In the detailed description below, this body is also denoted as a POM- ring without thereby reducing the choice of material of the ring or its functions. The term POM-ring may also comprise a rubber socket or a steel ring or collar or possibly with a seal arranged on the socket former and which is intended to be permanently embedded in the concrete wall when removing the formwork and the side core. The socket shaper which may be made of rubber, forms a ring shaped bead or bulb in the concrete wall where the seal or gasket is attached subsequent to the removal of the embedded socket shaper. The same type of shaping and seal/gasket ring may be applied to the end joint between a base section and a manhole section.

An object of the present invention is to provide a method for fabricating a lower section of manhole with an incorporated flow channel system providing an improved and cheaper overall solution.

Another object of the invention is to simplify planning and concreting of a lower section with an incorporated flow channel system in a manhole.

Yet another object of the present invention is to reduce the production cost of the socket joint by cutting or form casting a stem formed and cap formed moulding body, so that the one and the same solution through simple means may form the basis for obtaining a variety of variants and modifications.

Another object of the present invention is to provide a more adaptable solution giving an improved flexibility and a wider range of choices that can be adapted to specific requirements, and at the same time contributing to reduction of production costs.

An object of the invention is also to provide a modularized manhole in a flexible manner, so that the number of end terminations for a manhole may be reduced.

An even further object of the present invention is to reduce the number of variants of side cores necessary for fabricating all the various variants of pipe diameters, the end configurations of these and/or the type of seals to be employed.. The above objects are achieved by a method and a side core as defined by the accompanying independent claims, while variants, embodiments and alternative solutions are defined by the various dependent claims.

According to the invention, each side core for establishing the jointing apertures that extend through the wall of the manhole comprises:

- a first shaping element (the stem shaped body) having a cross sectional

shape which is configured so that at least the lower part of the inner cross section has a shape which is adapted to the lower shape of a downstream adjoining duct or channel or pipe, providing a smooth transition between the latter and former,

- a second shaping element (the cap shaped element) with an outer cross

sectional shape which mainly is configured so that the external cross sectional area is slightly larger than the outer diameter on the pointed spigot end of a pipe intended to be jointed in the jointing point within the concrete structure or unit, and

- a mainly cylinder or ring shaped, form stable body (the socket shaping body) which is configured to form contour in at least a part of the aperture through the concrete wall or structure, so that at least an inner, lower hydrodynamic surface may be formed in the transition area between an inner surface of the jointed spigot end of a jointed pipe and the adjoining downstream surface, and preferably with an external shape of said mainly cylindrically or ring shaped body being configured in such way that one or more supporting surfaces are established for attachment and locking of a sealing ring within the aperture in order to establish sealing lock and/or joint between the surrounding concrete wall of the aperture and spigot end of the pipe to be jointed,

wherein at least said first and second shaping body are removed subsequent to completed concreting.

According to one embodiment the cylindrically shaped, form stable body (the socket shaper) is arranged in the interface or transition zone between the first shaping element and the end surface of the second shaping element.

According to another embodiment, a strong magnet may be positioned at least at one free end of the side core body, preferably rigidly fixed to the side core and/or on the inner surface of the aperture, the magnet when the side core is placed in the formwork, being rigidly fixed to the inner surface of a steel formwork.

The socket shaper may preferably be removed subsequent to completed concreting and may be replaced by a more elastic sealing device of a suitable material, the cylindrical form stable body preferably being of a re-usable type. Alternatively an elastic seal, for example of rubber, may be used, such elastic seal serving as a permanent seal also subsequent to a completed concreting process.

According to an embodiment the first shaping element may be telescopically arranged in an aperture in the second shaping element.

For fabrication of the side cores, said first and/or the second shaping body may be formed by wire electrical discharge machining. Moreover the free end of the side core may be given a shape adapted to the shape of the adjoining moulding or forming element for the concrete structure, in order to enable formation of a sealed transition downstream of the concrete structure.

Moreover, according to the present invention a side core for establishing an aperture extending through the concrete structure is provided, serving as a joint within the concrete structure, the side core comprising:

- a first shaping element preferably with a circular cross section area, the lower shape of which preferably being adapted to the corresponding shape of a bottom of the downstream arranged channel in an adjoining unit;

- a second shaping element with a generally shaped circular cross sectional, the outer diameter of said circular cross section being somewhat larger than an outer diameter of the pointed spigot end of a pipe intended to be jointed with the concrete structure at a point of joint; and

- a mainly cylindrically shaped, form stable body with an inner diameter which is more or less adapted to the diameter of the pointed spigot end of the pipe to be jointed, so that at least a flow surface which is hydro dynamically smooth is provided, and preferably having an outer shape configured in such way that a supporting surface for attachment of a sealing ring is provided, thus establishing a sealed joint between the surrounding concrete wall and the pointed spigot end of the pipe to be jointed,

wherein the form stable body and at least the adjoining end of the second shaping element are intended to form a socket shaped contour and configuration inside the concrete wall.

According to one embodiment said first and second shaping body may be configured to be removed subsequent to completed concreting of concrete, and the cylinder shaped, form stable body may also be removed subsequent to completed concreting and be replaced by a more elastic, sealing device of a suitable sealing material.

Moreover, it should be appreciated that form stable body may be in the form of a mounted rubber gasket, such body being form stable when arranged on the first shaping body and configured to remain permanently mounted and partly embedded within the concrete wall subsequent to completed concreting and provided with an outwards projecting lip on an outer surface for embedment in the concrete during the concreting process.

Moreover, the first shaping element may advantageously be telescopically arranged within a correspondingly dimensioned aperture in the second shaping element.

An advantage with the present invention resides in a simplified concrete concreting process and also in that it is possible to reduce the required number of casting moulds in order to cover the existing range of variations in the various lower sections of the manholes.

Another advantage of the present invention is the possibilities of achieving a higher degree of accuracy and liquid tightness in the joint, while the fabrication costs are reduced.

Yet another advantage is a solution that the moulds need not be fabricated by using a moulding tool, but may be obtained by using a wire electrical discharge method and/or a milling process instead.

Brief Description of the Drawings

In the following some of the embodiments of the invention shall b described in more details, referring to the drawings where:

Figure 1 shows schematically in perspective, seen from above, a lower part of a completed, assembled base section of a manhole with jointed inlet pipes, an internally formed flow channel system and one single outlet pipe;

Figure 2 shows schematically in perspective a horizontal section through an embodiment of an manhole base section with an inner circular cross sectional area and a hexagonal outer, lower base slab;

Figure 3 shows schematically in perspective an example of a liquid flow channel formwork, milled out from polystyren and shown prior to installation in a formwork for further casting;

Figure 4 shows schematically, seen from a side in exploded position an example of a side core/socket prior to being mounted in an intended position on the liquid flow channel formwork;

Figure 5 shows schematically in perspective seen from below a liquid flow formwork with mounted side cores;

Figure 6a shows a vertical section through an assembled side core according to the invention; Figure 6b shows a corresponding view, also indicating one possible position of a magnet for fixation to the formwork;

Figure 7 shows a vertical section through an embodiment of a socket shaper according to the invention, where the socket shaper is of a type that may be re-used;

Figures 8a and 8b show schematically a horizontal section through a concrete wall with a side core with socket shaper and the same section with a concrete pipe partly inserted into the moulded aperture respectively, where a rubber gasket or seal being mounted on the socket shaper so that the socket shaper will become embedded in the concrete wall;

Figures 9a and 9b show schematically a second side core with a rubber collar as a socket shaper for establishing a void for the pointed spigot end and the rubber seal shown in Figure 9a, respectively, and with mounted rubber seal shown in Figure 9b;

Figures 10a and 10b show schematically a side core with socket shaper for a pipe where the seal is intended to be mounted on the pointed spigot end of a jointed pipe, and

Figure 1 1 to 15 show different, typical steps in a method for fabricating a manhole, where a side core according to the present invention is used. Detailed Description of an embodiment

In the following an embodiment of the solution according to the present invention shall be described. This embodiment is not intended to exhaustively disclose the invention, since the scope of protection is defined by what may be deducted from the attached patent claims.

Figure 1 shows schematically in perspective, seen from above, a base section

10 of an assembled concrete manhole with jointed inlet pipes 1 1 , internally arranged liquid flow channels 12 and one single exit pipe 13. The concrete manhole is of a type which for example in addition to the disclosed base section 10 may comprise one or more shaft rings (not shown), a tapered top or cone (not shown) placed on the top of the top shaft ring; possible a support ring (not shown; a converter slab (not shown) and a make up ring (not shown) with a cover on top, for example a cast iron lid. In the base section 10, a liquid flow channel system 12, which is upwards open and comprises branches 12' with a U-shaped cross section which extends from the end(s) of jointed inlet pipes 1 1 towards the inlet to the outlet pipe 13. The base section 10 is provided with an upwards open flow channels system 12 with branches 12' with U-shaped cross section extending from the end(s) of adjoining inlet pipes 1 1 to the inlet of an outlet pipe 13. In the embodiment shown, the base section 10 is configured to be connected with three inlet pipes 1 1 and is provided with an outlet pipe 13. As indicated in Figure 1 the liquid flow channels 12 in the base section 10 is upwards open and has a more or less U-shaped, smooth cross section without any sharp edges or transition zones which otherwise could create problems for the liquid flow through the manhole 10. Moreover the Figure indicates that the liquid flow channel 12 has an arced or curved shape in the horizontal plane, contributing to an improved hydrodynamic liquid flow into, through and out of the base section 10. It should be noted that the base section 10 with liquid flow channel system 12 is casted on one monolithic unit in one concreting process, where it preferably is used self compressing concrete, thereby securing high and uniform, even quality without any working joints. It should be noted, however, that as an alternative it is possible to use other types of concrete, as long as the end product meets the required quality, and that the liquid flow channel system as an alternative may be performed manually subsequent to casting of the concrete section 10.

At its upper end, the base section 10 is provided with a stepped end 14 and/or suitable sealing devices (not shown), in order to secure that the manhole is sealed off from unintentional inflow of water from the surroundings when the manhole is in installed state in the ground.

Figure 2 shows schematically a horizontal section through an embodiment of a manhole, where the only substantial difference with respect to the lower manhole section shown in Figure 1 being that the manhole according to Figure 2 is provided with an internal circular cross section and a hexagon shaped outer foot 35. The monolithic base section 10 may preferably be mass produced with prefabricated liquid flow channels 12 and sockets in the wall of the manhole for jointing of inlet pipes 1 1 (not shown) and an outlet pipe 14 (not shown). The inlet and outlet pipes 1 1 , 13 are of a conventional type having a spigot end configured to be jointed with a sockets shaped opposite end with an inner diameter that is adapted to the spigot end. Moreover, internally in the open aperture through the concrete section 10, a sealing ring (not shown) may preferably be mounted in order to establish a sealed connection with the surrounding concrete surface. According to the present invention an inner aperture extending through the wall during the casting process is

established, provided with socket shape in concrete wall of the manhole 10. This socket shape is configured to receive the spigot end of a pipe 1 1 , 13 in a sealing manner.

In stead of using a mould for forming the channel shape, a form made of a plastic material such as glass fiber reinforced plastics may be used, such form serving as a permanent part of the completed concreted base section without thereby deviating from the inventive idea. Moreover the formwork for shaping the wall of for example the base unit may either be of a reinforced plastic material or of steel. In case the formwork is made of steel, magnets may be attached to the side core at least at one end in order to fix the side core in proper or required position with respect to the formwork, thereby keeping the side core in position during concreting. Such magnet(s) may be a suitable remedy for preventing the side core to "float up" due to its low specific weight during concreting.

The solution shown in Figure 2 is provided with three inlet pipes 1 1 and an outlet pipe 13 and a liquid flow channel system 12 with three branches 12' meeting in a channel 12", connected to an aperture extending through the wall and provided with a corresponding integrated socket shaper. The flow channels 12 are given a curved shape. It should be noted, however, that the flow channel may have a straight shape. Correspondingly, it should be noted that according to the embodiment shown the sockets in the concrete wall may have a uniform diameter. It should be noted, however, that this diameter may be different, dependent on the diameter of the inlet pipes 1 1 .

Figure 3 shows schematically in perspective an example of a removable shape providing template 17 for a liquid flow channel 13 and the cross sectional shape of the channel 13, completely milled out from an expanded polystyrene (EPS) block, prior to installation as a mould for casting. According to the embodiment shown the template 17 comprises a plate 18 with an appropriate thickness; one from the plate 18 outwards extending shape providing body 19 given a shape which is configured to provide the required fluid flow channel during concreting. The end terminations of the shape providing body 19 are plane or slightly curved with a surface 20 being curved corresponding to the to the curve of the inner wall of the base section. On each of said surfaces a fixing device 21 is arranged for mounting of the shaping element (side core) 22, intended to form the aperture or recess extending through the concrete wall of the base section 10, intended for subsequent insertion and jointing of the pointed spigot end of an inlet pipe 12 or the

corresponding end on an outlet pipe 14. Said apertures are given a shape like a socket in order for establishing a joint with the pointed spigot end of a pipe 1 1 , 13. The inner shape of parts of the aperture is configured to function as a sealing socket joint in the concrete wall.

Figure 4 shows schematically in exploded mode a side view of an example of a side core 22 for attachment to the end of the outwards projecting shape providing body 19 on the plate 18. The side core 22 comprises a first body 16, hereafter named stem; a second body 23, hereafter named cap; and a ring shaped socket shaper 24, which made be made of POM, steel or rubber. Also other material with more or less shape permanence or shape stable materials may be used. Details of an embodiment of the side core 22 will be described in further details below, referring to Figures 6a and 7. The side core 22 may be provided with an aperture in the free end of the stem 22 in order to enable attachment in the attachment device 21. This aperture may have a shape that is adapted to the shape of the attachment device 21 . One end of the side core 22 may alternatively be glued to the end surface 20, so that use of a male plug 21 and a female plug 31 is avoided.

Figure 5 shows schematically in perspective a side view corresponding to the side view shown in Figure 3, but where a side core 22 with stem 16, POM-ring 24 and cap 23 are attached at the four jointing places. The view shown in Figure 5 is seen from below. As also indicated in Figure 5 the shaping element 22 is at the end intended to be attached to the end of the shape providing body 19 provided with attachment devices 21 . The attachment device may according to this embodiment consist of an aperture 31 with a square cross sectional area (the female part) in the end surface 22 and an outwards projecting male plug 21 in the adjoining end of the shape giving body 19.

Figure 6a shows schematically a vertical section through an embodiment of a side core 22 according to the invention. The side core 22 is seen from the side and is configured to be mounted at one end of an outwards projecting shaping element 19 on the plate 19 by means of a male part 21 and a female part 31. The side core 22 comprises a stem shaped part 16 and a cap shaped part 23. The outer diameter of the stem shaped part 16 corresponds more or less to the inner rounded shape of the adjacent U-shaped flow channel 12, so that when these element are assembled with the shape giving body 19 and placed in the formwork, a shape surface is preferably formed giving a smooth flow channel 12 without any sharp transition zones that may affect the flow of liquid along the flow channel 12 in a negative manner. The socket shaper 24 may also be made eccentric, so that it is in plane at the bottom with the channel or with the joint. In this way possible congestion/hindrance of the liquid flow across the joint may be reduced. At its free end the stem shaped body 16 is provided with a recess 31 that is given a shape adapted to the shape of the outwards projecting attachment device 21 arranged on the adjacent end surface 20 on the shape giving body 19, so that the side core 22 can be mounted on the shape giving body 19 when assembled. The cap shaped part 23 is preferably telescopically mounted at the one end of the stem shaped body 16. It should be noted, however, that according to another embodiment of the invention, the stem shaped body 16 and the cap shaped part 23 may be formed as one integrated body. Both the stem shaped body 16 and the cap shaped body 23 have a circular cross sectional area adapted to the shape of the fluid flow channel 19 and the pointed spigot end of an inlet pipe 1 1 into the manhole and outlet pipe 13 out of the manhole chamber 10 respectively. A ring shaped socket shaper 24 (for example a POM-ring) may be made of polyoxymethylene. The ring shaped socket shaper may have an inner diameter adjusted to the outer diameter of the stem 16 and also having an outer shape and diameter corresponding the corresponding inverse shape of the sealing (not shown) to be placed internally in the aperture extending through the concrete wall. In this way a socket shaped inner surface of the aperture through the concrete wall is obtained, adapted to the outer shape of the spigot end of a jointed inlet or outlet pipe 1 1 , 13. It is of importance that this socket shaper 24 has a high degree of rigidity and a high shape permanence, forming the basis for a solution that meets the requirement of low tolerance. A possible embodiment of the socket shaper 24 will be described below, referring to Figures 8 to 12. The end of the cap shaped body 23 intended to be placed adjoining the stem 16 may preferably be chamfered and the outer surface of this body 23 may moreover possibly be provided with a small draft angle or taper in order to ease removal of the cap shaped part 23 subsequent to completed concrete concreting.

Figure 6b shows a view corresponding to the one shown in Figure 6a, where the only difference being that according to Figure 6b a magnet 35 is fixed to the free end of cap23, i.e. the end intended to be in contact with the formwork 26 during concreting. As indicated the magnet 35 is placed inside the cavity 32, one end face of the magnet 35 being flush or inline with the end of the cap 23. Incidentally, it should be noted that a magnet may also be fixed to the free end of the stem 16, co- functioning as an attachment with a corresponding magnet to be arranged on the device for shaping the channels or to be in contact with the inner formwork, in case a socket is to be arranged at any position in a manhole wall or against a steel formwork for forming the inner liquid flow channel system.

For the solution according to the present invention it may be possible to vary the position of the socket shaper within the wall of the manhole, if so preferred. This is achieved by moving the cap shaped part 23 in axial direction along the stem 16. As indicated above, the cap 23 may have such outer diameter that a pipe inserted into the aperture arranged in the manhole wall may form an angle in the vertical axis of the manhole, either in a vertical plan and/or a horizontal plane, thus requiring somewhat more relaxed tolerance requirements during installation of the manhole 10, the inlet pipe 1 1 , and/or outlet pipe 13. The socket shaper 24 shown is co-axially arranged on the stem 16. It should be noted, however, that the socket shaper 24 may be formed eccentric and/or may be arranged in an eccentric position on the stem 24. As shown in Figure 6, the socket shaper 24 is configured to be in contact with the inner end of the cap 23.

Figure 7 shows a vertical section through an embodiment of a socket shaper

24 according to the present invention. It has an aperture extending through the socket shaper with an internal diameter, in this case in the order of 200 mm.

Moreover, the socket shaper 24 is provided with a ring shaped channel or recess 29, extending along the entire internal circumference of the aperture 28. This recess 29 may be used as fixing points for a tool for retraction of the socket shaper 24 subsequent to completed concreting. Moreover the socket shaper 24 is along its outer surface, at the end intended to face out of the manhole 10 in assembled state and in towards the stem 23, provided with a conical outer surface 30 which is transformed into a straight lined, cylindrical surface 34 or possibly slightly conical, in order to provide the required draft angle or taper when de-mounting upon completed concreting. The conical surface 30 may for example be shaped with a convex bead (not shown) extending along the entire outer circumference. The outer shape of the socket shaper 24 is given a shape intended to form a seat for and be adapted to the outer shape of a gasket (not shown) to be inserted in the moulded aperture upon completed concreting process. The linear or slightly conical cylindrical surface 30 may alternatively be slightly skewed inwards in direction away from the conical part 30 for establishing a draft angle or taper during the removal of the stem 16, socket shaper 24, and the cap 23 upon completed concreting. Moreover, the free outer end edge 33 of the straight linear cylindrically shaped parts 34 may preferably be rounded. The inner surface 27 of the socket shaper 24 has a shape and aperture 28 with a diameter adapted to the outer diameter of the stem 16.

The figures 8a and 8b show schematically a horizontal section through a concrete wall 10 with a side core 22 with a socket shaper 24 corresponding to the one shown in Figures 6a, 6b and 7 and where the same section is shown in Figure 8b with a concrete tube 13 - in this case an outlet pipe, partly inserted in the aperture 15. For this solution, a sealing ring 37 is attached to the socket shaper prior to placing in the formwork, so that the sealing ring 37 will be embedded in the concrete wall. The sealing ring is for this purpose provided with fins or the like (not shown) in order to secure fixation and proper fixture in the concrete wall.

Correspondingly, Figures 9a and 9b show a solution where a rubber socket 24 is used as a socket shaper prior to placing in the formwork and concreting. For this solution the socket shaper is given a different shape. Moreover, the rubber socket is given a shape adapted to the thickness of the pipe wall and in addition to the shape of a rubber sealing 38 to be places subsequent to completed concreting process. Here, the socket 24 is pulled out after removal of the cap 23 and the stem, and the sealing 38 installed in the slot formed by the rubber socket 24 is intended to give a void for the sealing 38, ref. Figure 9b. Figure 9b shows in addition PVC/PP-pipe, ready for installation in the aperture 15 with sealing 38.

Figure 10 a shows schematically a side core with a socket shaper 22 intended for a pipe where the sealing has to be attached to the spigot end of a jointed pipe, prior to insertion into the concrete wall. Here, the socket shaper 24 has a shape that corresponds to the socket of the pipe 1 1 . The type of pipe 1 1 may for example be a double walled plastic pipe or a concrete pipe. Figure 10b shows schematically the spigot end of a pipe 1 1 with attached sealing 39, made ready for mounting. Common for all these variants is that the at least inner lower surface of the inlet pipes 1 1 and the inner radius of the outlet pipe 13 are aligned with the at least the lower surface formed by the stem shaped body 16 of the concrete wall downstream the ends of the inlet pipes 1 1 /upstream of the outlet pipe 13. If it also a flow channel duct within the concrete section is established, then the lower surfaces of the flow channel duct also is aligned correspondingly with the apertures of the concrete wall. In Figures 8-10, the cap shaped body 23 is shown in a position where the cap shaped body projects beyond the outer surface of the concrete wall. It should be noted, however, that the part of the cap shaped body 23 shown with dotted lines, is cut by a wire electrical discharge machine prior to assembling, so that the free end of the cap shaped body 23 will be aligned with the inner surface of the outer part of the formwork.

In the following a method for concreting of a base section in a manhole of concrete shall be described in further detail referring to the figures 1 1 to 15, showing different typical steps in a method for fabricating an manhole according to present invention.

Firstly a supporting structure 25 in the form of a cylindrical body with a smooth vertical outer surface is positioned on a flat and horizontal plate. The diameter of the cylindrical body 25 corresponds to the inner diameter of the base section 10 and may be internally stiffened or reinforced (not shown), so that the cylindrical body is form stable. Thereupon a shape providing body or mould 17 for the low channel 13 is placed on top of the cylindrical body 25. The shape providing body 17 is provided with an upwards facing convex mould for formation of the low channels 12 upon concreting. The part of the shape providing body 17 for the inlet pipes 1 1 and the outlet pipe 13 is formed such that the end surfaces 20 are flush with the vertical outer cylindrical surface of the supporting cylindrical body 25. Thereupon, a side core 22 is placed on the end surfaces 20. This side core is designed for formation of a profiled aperture through the wall of the manhole during concreting. This is done by inserting a four sided female end/aperture 31 on the side core 22 onto the four edged male plug 21 at the ends 20 of the shape giving body 19. The length of the side core 22 in mounted state corresponds to at least the wall thickness of the lower base part 10, the free ends of which being curved in accordance with the inner curvature of the outer formwork 26. Then the outer formwork 26 is positioned around the cylindrical supporting body 25. This externally arranged outer form 26 may be split in two (Figure 12) and is locked together by means suitable locking device (not shown).

As shown in Figure 12 it is a distance from the cylinder 25 with the shape providing body 17 and up to the upper end of the outer formwork, while at the same time an annulus is being formed around the central supporting body 25. When concreting concrete, such as for example self compressive concrete, into the formwork in this position, the concrete will firstly be filled into the annulus between the inner vertical surface of outer formwork 26 and the outer surface of the

supporting cylindrical body 25. Thereupon, more concrete is concreted into the form in the same concreting operation until the concrete is in level with the upper rim of the outer formwork 26. In this operation the concrete will also fill in the space around the side cores 22 and the bottom surface 27 of the base section 10 (Figure 13). Even if it is specified that the concrete is concreted completely up to the rim of the outer form, it shall be appreciated that the concrete does not necessarily have to be filled up to this level.

Upon completed concreting in the formwork, the formwork with concrete is allowed to cure for 24 hours. Thereupon the formwork (see Figure 13) is turned upside down and the two sections of the outer formwork 26 are then removed, so that the cured manhole is exposed. The shape providing section 17 is then removed, for example by firstly to cut the connections 21 ,31 for example by a thermal knife, and the lift out the shape giving section 17. The stem shaped body 16 and the cap shaped body 23 are then pulled radially out of the wall of the manhole (Figure 14).

The lower base part 10 is now ready for placing in a ditch, as indicated in Figure 15. In order to prepare for the installation a sealing gasket may be placed in the profiled recess formed by the socket former 24 during the concreting process. The spigot end of a pipe 1 1 , 13 with a socket may now be inserted into the socket shaped aperture and into the gasket within the socket joint of the concrete wall.

In the concreting process the gasket or seal may be placed on the stem shaped body 16 instead of or in addition to the shape providing body 24 prior to concreting. In such case the gasket may be provided with outwards extending and projecting fins extending along the periphery of the ring shaped gasket, intended to be embedded in the concrete and to secure fixture to the concrete. Alternatively, the sealing may be inserted into the aperture at the required and intended position subsequent to completed concreting, the sealing thus substituting the form stable shape providing body otherwise used and removed.

Even though a solution intended for use in connection with a base section with a flow channel system is described, it should be appreciated that the present solution also may be used for other types of joints in a concrete section being provided with an aperture extending through a concrete wall and being provided with a pipe joint or pipe termination. If for example a socket joint is intended to be arranged as a sealed termination in a manhole or in a concrete structure, the shape providing body 22 may be placed and locked or fixed in position in a sealing manner between the inner formwork and the outer formwork, the end surfaces of the shape providing body thus being given a shape adapted to the curvature of the shape of the inner walls of the mould, so as to establish a sealed joint. The shape providing body 22 is in such case positioned at a desired place in the formwork.

For a socket it is the diameter that is a governing parameter, requiring small or tight tolerances, both with respect to roundness and diameter. This is in particular, but not only, relevant for the diameter where the seal or gasket is intended o be positioned. The diameter should not deviate more than 0,5 mm at the most at the seat for the sealing and for the largest diameter pipes to be jointed, the split between the socket and the spigot end should not be larger than in the order of 2 to 3 mm, preferably less.

It should be appreciated that the formwork preferably may be made of steel.

Claims

1 . Method for fabricating a socket joint for a pipe to be jointed in a concrete wall or concrete structure, such as for example a lower section (10) of a branching chamber or manhole, where prior to concreting a side core (22) is established, the side core (22) being given an external shape or contour adapted to the shape or contour to be established in an aperture extending through the concrete wall or structure, and where the side core (22) for said joint being positioned at the required place between an outer formwork and an inner formwork for subsequent concreting, whereupon the side core (22) is removed upon completed concreting,

c h a r a c t e r i z e d i n that the side core (22) for the joint comprises:

- a first shape providing element (16) with a cross section that is configured such that the lower part of the cross section has a shape substantially adapted to a lower part of a downstream adjoining channel or duct (12', 12") inside the manhole , so that at least a lower hydro dynamical surface is formed between an internal surface of a spigot end of an adjoining pipe and a consecutive downstream surface inside the manhole;

- a second shape providing element (23) with an outer cross section which mainly is configured to in such way that the outer cross section is slightly larger than the outer diameter of a spigot end of a pipe (1 1 , 13) to be jointed in the joint in the concrete wall or structure, and

- a mainly ring shaped, form stable body (24) configured to form an internal shape or contour of the aperture through the concrete wall or structure, preferably having an outer shape that is configured in such way that one or more support surfaces are established for fixing of a sealing ring within the aperture for establishing a sealing fixation and/or joint between the

surrounding concrete wall and the spigot end of the pipe (1 1 , 13) to be jointed, wherein at least said first and second shape providing body (16,23) are removed subsequent to completed concreting.

2. Method according to claim 2, wherein the cylindrically or ring shaped, form stable body (24) is arranged in the transition zone between the first shape providing element (16) and an end surface on the second shape providing element (23).

3. Method according to claim 1 or 2, wherein the ring shaped, shape stable body (24) is removed subsequent to completed concreting and replaced by a more or less elastic, sealing gasket of a suitable material, the ring shape stable body (24) preferably being re-usable.

4. Method according to claim 1 or 2, wherein an elastic socket, for example made of rubber is used, the socket having a ring shaped bead and that the socket is removed subsequent to completed concreting and that a more or less elastic and sealing gasket (38) of a suitable material is mounted in a recess formed by the socket (24) subsequent to the removal of the socket (24) for possible re-use.

5. Method according to one of the claims 1 to 4, wherein the first shape providing element (16) is telescopically arranged in an aperture (32) in the second shape providing body (23).

6. Method according to one of the claims 1 to 5, wherein the first (16) and/or second (23) shape providing body is produced by using a wire electrical discharge technique or casting.

7. Method according to one of the claims 1 to 6, wherein the free end of the stem shaped body (22) is given a shape adapted to the shape of adjoining flow channel shaping element (19) for the concrete structure, in order to form a smooth transition downstream of the concrete wall.

8. Method according to one of the claims 1 to 7, wherein a magnet (35) is fixed at least to one end of the side core (22) in order to maintain the side core (22) in fixed position during the concreting stage.

9. Side core (22) for establishing a joint in an aperture extending through a wall of a concrete structure (10), comprising a side core (22) intended to be mounted in connection with a mould for concreting the concrete structure (10) and which more or less is removed upon completed concreting,

c h a r a c t e r i z e d i n that the side core (22) comprises:

- a first shape providing element (16) with preferably a circular cross section, the lower shape of which preferably being configured to the lower shape of a bottom of a downstream adjoining channel (12Ί 2");

- a second shape providing element (23) with a mainly circular cross section, the outer diameter of which being slightly larger that the outer diameter of a spigot end of an adjoining pipe (1 1 , 13) intended to be jointed with the concrete structure (10) at a joint; and

- one mainly ring shaped, form stable body (24) with an inner diameter which is mainly adapted to the diameter of the spigot end on the pipe (1 1 , 13) intended to be jointed, so that at least a lower flow path which is hydro dynamically smooth is provided, preferably with an outer shape that is configured in such way that a supporting surface is established and with a fixing surface for a sealing ring, establishing a liquid tight joint between the surrounding concrete wall and the spigot end of the pipe (1 1 ,13) intended to be jointed.

10. Side core (22) according to claim 9, wherein the first (16) and second (23) shape providing body is configured to be removed subsequent to completed concreting, and where the ring shaped, form stable body (24) is removed upon completed concreting and replaced by a more or less elastic sealing gasket of a suitable material.

1 1 . Side core according to claim 9 or 10, wherein the form stable socket former (24) comprises a sealing ring (24) configured to be embedded in the surrounding concrete and to remain in position upon removal of the socket former (24).

12. Side core (22) according to claim 9, wherein the form stable body (24) is made of a rubber socket (24) mounted on the stem shaped body (16) prior to being placed in the formwork and where the rubber socket (24) preferably is given a shape adapted to the thickness of the concrete wall and the shape of a sealing (38), the rubber socket (24) being removed upon completed concreting and replaced by a gasket.

13. Side core (22) according to one of the claims 9 to 12, wherein the first shape providing element (16) is telescopically arrange in an aperture (32) in the second shape providing element (23).

14. Side core (22) according to one of the claims 9 to 13, wherein a magnet is fixed at least to one end of the side core (22).

15. Side core (22) according to claim 14, wherein the magnet is arranged inside an aperture of the side core(22), the free end of the magnet being configured to be more or less flush with the surface of the side core (22).